US20080257424A1

US20080257424A1 - Flow Valve Port for a Gas Regulator

Info

Publication number: US20080257424A1
Application number: US12/105,825
Authority: US
Inventors: Erik M. Quijano
Original assignee: Fisher Controls International LLC
Current assignee: Fisher Controls International LLC
Priority date: 2007-04-20
Filing date: 2008-04-18
Publication date: 2008-10-23
Also published as: RU2009140597A; AR066141A1; BRPI0810027B1; CA2683022A1; AU2008242692B2; WO2008131248A1; CA2683022C; EP2463740A1; JP5285063B2; ATE550704T1; CN105179793B; EP2140328A1; JP2010525290A; CN101663627B; BRPI0810027A2; AU2008242692A1; EP2463740B1; RU2488873C2; CN101663627A; CN105179793A

Abstract

A fluid regulating device comprises a valve body carrying a valve port that defines an elongated orifice that converges from an inlet portion to an outlet portion. The converging orifice minimizes the effects of boundary layer separation and advantageously maximizes the flow capacity of the valve port. The elongated orifice can be defined by a one-piece body, which is threaded into the valve body, or by a cartridge slidably disposed in a housing, which is threaded into the valve body. The fluid regulating device further comprises a diaphragm-based actuator including a control element movably disposed within the valve body for controlling the flow of fluid therethrough.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The priority benefit of U.S. Provisional Patent Application No. 60/913,123, entitled “Improved Flow Valve Port for a Gas Regulator,” filed Apr. 20, 2007, is claimed and the entire contents thereof are expressly incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to gas regulators, and more particularly, to gas regulators having regulator valves with removable valve ports.

BACKGROUND

The pressure at which typical gas distribution systems supply gas may vary according to the demands placed on the system, the climate, the source of supply, and/or other factors. However, most end-user facilities equipped with gas appliances such as furnaces, ovens, etc., require the gas to be delivered in accordance with a predetermined pressure, and at or below a maximum capacity of a gas regulator that may be installed in the system. Such gas regulators are implemented into these distribution systems to ensure that the delivered gas meets the requirements of the end-user facilities. Conventional gas regulators generally include a closed-loop control actuator for sensing and controlling the pressure of the delivered gas.
In addition to a closed loop control, some conventional gas regulators include a relief valve. The relief valve is adapted to provide over pressure protection when the regulator or some other component of the fluid distribution system fails, for example. Accordingly, in the event the delivery pressure rises above a predetermined threshold pressure, the relief valve opens to exhaust at least a portion of the gas to the atmosphere, thereby reducing the pressure in the system.
FIG. 1 depicts one conventional gas regulator 10. The regulator 10 generally comprises an actuator 12 and a regulator valve 14. The regulator valve 14 defines an inlet 16, an outlet 18, and a throat 11. The inlet 16 is for receiving gas from a gas distribution system, for example. The outlet 18 is for delivering gas to an end-user facility such as a factory, a restaurant, an apartment building, etc. having one or more appliances, for example. Additionally, the regulator valve 14 includes a valve port 136 carried by the throat 11 and disposed between the inlet 16 and the outlet 18. Gas must pass through the valve port 136 to travel between the inlet 16 and the outlet 18 of the regulator valve 14.
The actuator 12 is coupled to the regulator valve 14 to ensure that the pressure at the outlet 18 of the regulator valve 14, i.e., the outlet pressure, is in accordance with a desired outlet or control pressure. The actuator 12 is therefore in fluid communication with the regulator valve 14 via a valve mouth 34 and an actuator mouth 20. The actuator 12 includes a control assembly 22 for sensing and regulating the outlet pressure of the regulator valve 14. Specifically, the control assembly 22 includes a diaphragm 24, a piston 32, and a control arm 26 having a valve disc 28. The valve disc 28 includes a generally cylindrical body 25 and a sealing insert 29 fixed to the body 25. The diaphragm 24 senses the outlet pressure of the regulator valve 14. The control assembly 22 further includes a control spring 30 in engagement with a top-side of the diaphragm 24 to offset the sensed outlet pressure. Accordingly, the desired outlet pressure, which may also be referred to as the control pressure, is set by the selection of the control spring 30.
The diaphragm 24 is operably coupled to the control arm 26, and therefore the valve disc 28, via the piston 32, and controls the opening of the regulator valve 14 based on the sensed outlet pressure. For example, when an end user operates an appliance, such as a furnace that places a demand on the gas distribution system downstream of the regulator 10, the outlet flow increases, thereby decreasing the outlet pressure. Accordingly, the diaphragm 24 senses this decreased outlet pressure. This allows the control spring 30 to expand and move the piston 32 and the right-side of the control arm 26 downward, relative to the orientation of FIG. 1. This displacement of the control arm 26 moves the valve disc 28 away from the valve port 136 to open the regulator valve 14. So configured, the appliance may draw gas through the valve port 136 toward the outlet 18 of the regulator valve 14, as demand may be required for operation.
FIG. 1A depicts the conventional valve port 136 of the conventional regulator 10 installed within the throat 11 of the regulator valve 14 depicted in FIG. 1. The valve port 136 depicted in FIG. 1A includes a one-piece body having a valve seat 138, a hexagonal nut portion 140, and a body portion 142. The valve seat 138 protrudes from the nut portion 140 and is adapted to be engaged by the valve disc 28 to close the regulator valve 14. The body portion 142 includes a plurality of external threads 143 in threaded engagement with the throat 11 of the regulator valve 14. So configured, the valve port 136 is removable from the regulator valve 14 such that it may be replaced with a different valve port having a different configuration to tailor operational and flow characteristics of the regulator valve 14 to a specific application.
Additionally, the valve port 136 of the conventional embodiment depicted in FIG. 1A defines an elongated orifice 144 for allowing the passage of gas through the regulator valve 14. The orifice 144 is a cylindrical bore of substantially uniform diameter D1 including an inlet 144 a and an outlet 144 b. The inlet 144 a includes a chamfered inner surface 148. So configured, gas flows through the conventional valve port 136 in accordance with a flow path, which may be indicated by flow arrows 146 in FIG. 1A. More particularly, the flow of gas enters the inlet 144 a of the orifice 144 and exits the outlet 144 b. However, due to basic concepts of fluid dynamics such as the boundary layer effect, the flow of the gas follows the flow arrows 146, which, as illustrated, separate from the sidewalls of the orifice 144 toward the outlet 144 b. Thus, the orifice 144 has an effective diameter D2, which is defined by the flow of gas emerging from the outlet 144 b. The effective diameter D2 is less than actual diameter D1. Therefore, the maximum potential flow capacity of the orifice 144 and the valve port 136 is not realized.
FIG. 2 depicts an alternative conventional valve port 236, which is adapted to provide both a primary seal and a secondary, or back-up seal. The valve port 236 generally includes a housing 260, a cartridge 262, and a spring 264. The cartridge 262 is slidably disposed within the housing 260 and includes an inlet 262 a, an outlet 262 b, and an elongated orifice 244. The orifice 244 is generally cylindrical and includes an inlet portion 244 a and an outlet portion 244 b. In the embodiment depicted in FIG. 2, the inlet portion 244 a has a uniform diameter D1 that is slightly larger than a uniform diameter D2 of the outlet portion 244 b. Additionally, in the depicted embodiment, the inlet 262 a of the cartridge 262 includes a chamfered inner surface 292. The spring 264 biases the cartridge 262 into the position depicted in FIG. 2, which corresponds to the valve port 236 providing the primary seal, as will be described below. So configured, gas flows through the conventional valve port 236 in accordance with a flow path, which may be indicated by flow arrows 246. More particularly, the flow of gas enters the inlet portion 244 a of the orifice 244 and exits the outlet portion 244 b. However, due to basic concepts of fluid dynamics such as boundary layer separation, the flow of the gas follows the flow arrows 246. Specifically, the gas separates from the sidewalls of the orifice 244 as it reaches the outlet portion 244 b of the orifice 244. Thus, the outlet portion 244 a of the orifice 244 has an effective diameter D3, which is defined by the flow of gas emerging from the outlet portion 244 b. The effective diameter D3 is less than the actual diameter D1. Therefore, similar to the valve port 136 described above with reference to FIG. 1A, the maximum potential flow capacity of the orifice 244 and the valve port 236 is not completely realized.
With continued reference to FIG. 2, the housing 260 includes a hollow, generally cylindrical housing having a hexagonal nut portion 266, a body portion 268, and a curtain portion 270. The body portion 268 includes an internal bore 274 accommodating the cartridge 262. The body portion 268 further includes a plurality of external threads 272 for being threadably coupled into the throat 11 of the regulator valve 14, as depicted. The nut portion 266 of the housing 262 is therefore adapted to be engaged by a tool such as a pneumatic ratchet to install the valve port 236 into the throat 11 of the regulator valve 14. The curtain portion 270 includes a plate 280 spaced from the body portion 268 of the housing 262 by a pair of legs 282. The plate 280 carries a secondary seat 271 including a rubber surface 273, for example. So configured, the curtain portion 270 defines a pair of windows 284 in the housing 260. The windows 284 allow for the flow of gas into the valve port 236 and through the regulator valve 14.
Accordingly, during a normal operational condition, the outlet 262 b of the cartridge 262 serves as a primary seat and is adapted to be engaged by the valve disc 28 of the control assembly 22 to stop the flow of fluid through the regulator valve 14. However, in the event that debris or some other type of foreign material becomes lodged between the valve disc 28 and the outlet 262 b of the cartridge 262 when the valve disc 28 attempts to seal against the cartridge 262, the primary seal fails to stop the flow of gas through the valve port 236. Thus, the pressure downstream of the regulator 10, i.e., the outlet pressure, increases. This increase in pressure is sensed by the diaphragm 24 which further causes the valve disc 28 to be forced toward the valve port 236. This force eventually overcomes the force of the spring 264 and displaces the cartridge 262 into the housing 260 such that the inlet 262 a engages the rubber surface 273 of the secondary seat 271. So configured, the secondary seat 271 of the housing 260 seals the inlet 262 a and blocks the flow of gas through the windows 284 in the housing 260, thereby preventing the flow of gas through the cartridge 262 and the regulator valve 14.
Once a downstream demand is placed back on the system however, the diaphragm 24 senses a decrease in outlet pressure and moves the valve disc 28 away from the valve port 236. The spring 264 biases the cartridge 262 back to the position depicted in FIG. 2 and any debris previously lodged between the valve disc 28 and the outlet 262 a of the cartridge 262 releases and flows downstream.
Referring back to FIG. 1 and as mentioned above, the conventional regulator 10 further functions as a relief valve. Specifically, the control assembly 22 includes a relief spring 40 and a release valve 42. The diaphragm 24 includes an opening 44 through a central portion thereof and the piston 32 includes a sealing cup 38. The relief spring 40 is disposed between the piston 32 and the diaphragm 24 to bias the diaphragm 24 against the sealing cup 38 to close the opening 44, during normal operation. Upon the occurrence of a failure such as a break in the control arm 26, for example, the control assembly 22 is no longer in direct control of the valve disc 28 and the flow through the regulator valve 14 moves the valve disc 28 into an extreme open position. This allows a maximum amount of gas to flow into the actuator 12. Thus, as the gas fills the actuator 12, pressure builds against the diaphragm 24 forcing the diaphragm 24 away from the sealing cup 38, thereby exposing the opening 44. The gas therefore flows through the opening 44 in the diaphragm 24 and toward the release valve 42. The release valve 42 includes a valve plug 46 and a release spring 54 biasing the valve plug 46 into a closed position, as depicted in FIG. 1. Upon the pressure within the actuator 12 and adjacent the release valve 42 reaching a predetermined threshold pressure, the valve plug 46 displaces upward against the bias of the release spring 54 and opens, thereby exhausting gas into the atmosphere and reducing the pressure in the regulator 10.
One consideration in selecting a regulator for use in a particular application includes maximizing flow capacity at the set outlet, or control, pressure. However, as discussed above, the orifices 144, 244 of the conventional valve ports 136, 236 discussed above have effective diameters that are less than the respective actual diameters, and therefore, the full potential flow capacities are not realized.

SUMMARY

The present invention provides a regulator and/or a valve port for a regulator. The regulator generally comprises an actuator and a valve body. The actuator includes a moveable valve disc. The valve port is disposed within the valve body. The actuator displaces the valve disc relative to the valve port for controlling the flow of fluid through the valve body. The valve port includes an orifice for allowing the passage of fluid through the valve body.
One aspect of the valve port may include an orifice including an inlet portion and an outlet portion. The inlet portion may include an inner sidewall that converges from an enlarged inlet aperture toward the outlet portion. So configured, the inlet portion forces the flow of fluid through the valve port to maximize the flow capacity.
In another aspect of the valve port of the present invention, the inlet portion of the orifice may include a longitudinal dimension substantially greater than a longitudinal dimension of the outlet portion.
Another aspect of the present invention may further include a valve port comprising a housing and a cartridge slidably disposed within the housing for providing a primary and a secondary seal, wherein the cartridge may define an orifice with an inner sidewall that converges from an enlarged inlet aperture toward an outlet. So configured, the converging sidewall forces the flow of fluid through the valve port to maximize the flow capacity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view of a conventional regulator including one conventional valve port;

FIG. 1A is a side cross-sectional view of a regulator valve of the regulator of FIG. 1 including the conventional valve port of FIG. 1 and taken from circle I-A of FIG. 1;

FIG. 2 is a side cross-sectional view of another conventional valve port adapted for use with the regulator of FIG. 1;

FIG. 3 is a side cross-sectional view of a regulator including a valve port, the regulator and valve port constructed in accordance with a first embodiment of the present invention;

FIG. 3A is a side cross-sectional view of a regulator valve of the regulator of FIG. 3 illustrating the valve port of the first embodiment of the present invention and taken from circle III-A of FIG. 3;

FIG. 4 is a side cross-sectional view of a valve port constructed in accordance with a second embodiment of the present invention; and

FIG. 5 is a side cross-sectional view of a cartridge for use in a valve port constructed in accordance with a third embodiment of the present invention.

DETAILED DESCRIPTION

FIG. 3 depicts a gas regulator 300 constructed in accordance with one embodiment of the present invention. The gas regulator 300 generally includes an actuator 302 and a regulator valve 304. The regulator valve 304 includes an inlet 306 for receiving gas from a gas distribution system, for example, and an outlet 308 for delivering gas to a facility having one or more appliances, for example. The actuator 302 is coupled to the regulator valve 304 and includes a control assembly 322 having a control element 327. During a first or normal operational mode, the control assembly 322 senses the pressure at the outlet 308 of the regulator valve 304, i.e., the outlet pressure, and controls a position of the control element 327 such that the outlet pressure approximately equals a predetermined control pressure. Additionally, upon the occurrence of a failure in the system such as a breakage of one of the components of the control assembly 322, the regulator 300 performs a relief function that is generally similar to the relief function described above with reference to the relief valve 42 of the regulator 10 depicted in FIG. 1.
With continued reference to FIG. 3, the regulator valve 304 further includes a throat 310 and a valve mouth 312. The throat 310 is disposed between the inlet 306 and the outlet 308 and accommodates a valve port 336. The valve mouth 312 defines an opening 314 disposed along an axis that is generally perpendicular to an axis of the inlet 306 and outlet 308 of the regulator valve 304. The valve port 336 includes an inlet end 350, an outlet end 352, and an elongated orifice 344 extending between the inlet end 350 and the outlet end 352. Gas must travel through the orifice 344 in the valve port 336 to travel between the inlet 306 and the outlet 308 of the regulator valve 304. The valve port 336 is removable from the regulator valve 304 such that it may be replaced with a different valve port having a different configuration to tailor operational and flow characteristics of the regulator valve 304 to a specific application.
The actuator 302 includes a housing 316, and the control assembly 322, as mentioned above. The housing 316 includes an upper housing component 316 a and a lower housing component 316 b secured together with a plurality of fasteners (not shown), for example. The lower housing component 316 b defines a control cavity 318 and an actuator mouth 320. The actuator mouth 320 is connected to the valve mouth 312 of the regulator valve 304 to provide fluid communication between the actuator 302 and the regulator valve 304. In the disclosed embodiment, the regulator 300 includes a collar 311 securing the mouths 312, 320 together. The upper housing component 316 a defines a relief cavity 334 and an exhaust port 356. The upper housing component 316 a further defines a tower portion 358 for accommodating a portion of the control assembly 322, as will be described.
The control assembly 322 includes a diaphragm subassembly 321, a disc subassembly 323, and a relief valve 342. The diaphragm subassembly 321 includes a diaphragm 324, a piston 332, a control spring 330, a relief spring 340, a combination spring seat 364, a relief spring seat 366, a control spring seat 360, and a piston guide 359.
More particularly, the diaphragm 324 includes a disc-shaped diaphragm defining an opening 344 through a central portion thereof. The diaphragm 324 is constructed of a flexible, substantially air-tight, material and its periphery is sealingly secured between the upper and lower housing components 316 a, 316 b of the housing 316. The diaphragm 324 therefore separates the relief cavity 334 from the control cavity 318.
The combination spring seat 364 is disposed on top of the diaphragm 324 and defines an opening 370 positioned concentric with the opening 344 in the diaphragm 324. As depicted in FIG. 3, the combination spring seat 364 supports the control spring 330 and the relief spring 340.
The piston 332 of the disclosed embodiment includes a generally elongated rod-shaped member having a sealing cup portion 338, a yoke 372, a threaded portion 374, and a guide portion 375. The sealing cup portion 338 is concaved and generally disc-shaped and extends circumferentially about a mid-portion of the piston 332, and is located just below the diaphragm 324. The yoke 372 includes a cavity adapted to accommodate a coupler 335 which connects to a portion of the disc subassembly 323 to enable attachment between the diaphragm subassembly 321 and the disc subassembly 323, as will be described.
The guide portion 375 and the threaded portion 374 of the piston 332 are disposed through the openings 344, 370 in the diaphragm 324 and the combination spring seat 364, respectively. The guide portion 375 of the piston 332 is slidably disposed in a cavity in the piston guide 359, which maintains the axial alignment of the piston 332 relative to the remainder of the control assembly 322. The relief spring 340, the relief spring seat 366, and a nut 376, are disposed on the threaded portion 374 of the piston 332. The nut 376 retains the relief spring 340 between the combination spring seat 364 and the relief spring seat 366. The control spring 330 is disposed on top of the combination spring seat 364, as mentioned, and within the tower portion 358 of the upper housing component 316 a. The control spring seat 360 is threaded into the tower portion 358 and compresses the control spring 330 against the combination spring seat 364.
In the disclosed embodiment, the control spring 330 and the relief spring 340 include compression coil springs. Accordingly, the control spring 330 is grounded against the upper housing component 316 a and applies a downward force to the combination spring seat 364 and the diaphragm 324. The relief spring 340 is grounded against the combination spring seat 364 and applies an upward force to the relief spring seat 366, which in turn is applied to the piston 332. In the disclosed embodiment, the force generated by the control spring 330 is adjustable by adjusting the position of the control spring seat 360 in the tower portion 358, and therefore the control pressure of the regulator 300 is also adjustable.
The control spring 330 acts against the pressure in the control cavity 318, which is sensed by the diaphragm 324. As stated, this pressure is the same pressure as that which exists at the outlet 308 of the regulator valve 304. Accordingly, the force applied by the control spring 330 sets the outlet pressure to a desired, or control pressure for the regulator 300. The diaphragm subassembly 321 is operably coupled to the disc subassembly 323, as mentioned above, via the yoke 372 of the piston 332 and the coupler 335.
The disc subassembly 323 includes a control arm 326 and a stem guide 362. The control arm 326 includes a stem 378, a lever 380, and the control element 327. The control element 327 of the disclosed embodiment includes a valve disc 328 with a seating surface 388. The stem 378, the lever 380, and the valve disc 328 are constructed separately and assembled to form the control arm 326. Specifically, the stem 378 is a generally linear rod having a nose 378 a and a recess 378 b, which in the disclosed embodiment is generally rectangular. The lever 380 is a slightly curved rod and includes a fulcrum end 380 a and a free end 380 b. The fulcrum end 380 a includes an aperture 384 receiving a pivot pin 386 carried by the lower housing component 316 b. The fulcrum end 380 a also includes a knuckle 387 having an elliptical cross-section and disposed within the recess 378 b of the stem 378. The free end 380 b is received between a top portion 335 a and a pin 335 b of the coupler 335 that is attached to the yoke 372 of the piston 332. Thus, the coupler 335 operably connects the disc subassembly 323 to the diaphragm subassembly 321.
The stem guide 362 includes a generally cylindrical outer portion 362 a, a generally cylindrical inner portion 362 b, and a plurality of radial webs 362 c connecting the inner and outer portions 362 b, 362 a. The outer portion 362 a of the stem guide 362 is sized and configured to fit within the mouths 312, 320 of the regulator valve 304 and lower housing component 316 b. The inner portion 362 b is sized and configured to slidably retain the stem portion 378 of the control arm 326. Thus, the stem guide 362 serves to maintain the alignment of the regulator valve 304, the actuator housing 316, and the control assembly 322, and more particularly, the stem 378 of the control arm 326 of the control assembly 322.
FIG. 3 depicts the control assembly 322 in a normally operational closed position, where there is no demand placed on the system downstream of the regulator 300. Therefore, the seating surface 388 of the valve disc 328 sealingly engages the outlet end 352 of the valve port 336. So configured, gas does not flow through the valve port 336. This configuration is achieved because the outlet pressure, which corresponds to the pressure in the control cavity 318 of the housing 316 and sensed by the diaphragm 324, is greater than the force applied by the control spring 330. Accordingly, the outlet pressure forces the diaphragm 324, the piston 332, and the valve disc 328 into the closed position depicted.
However, in the event that an operating demand is placed on the system, e.g., a user begins operating an appliance such as a furnace, a stove, etc., the appliance draws gas from the control cavity 318 of the regulator 300, thereby reducing the pressure that is sensed by the diaphragm 324. As the pressure sensed by the diaphragm 324 decreases, a force imbalance occurs between a control spring force and an outlet pressure force on the diaphragm 324 such that the control spring 330 expands and displaces the diaphragm 324 and piston 332 downward, relative to the housing 316. This causes the lever 380 to pivot in the clockwise direction about the pivot pin 386, which, in turn, rotates the knuckle 387 relative to the recess 378 b in the stem 378. This moves the valve disc 328 away from the outlet end 352 of the valve port 336 to open the regulator valve 304. So configured, the gas distribution system is able to deliver gas to the downstream appliance through the regulator valve 304 at a control pressure that is set by the control spring 330. Additionally, the diaphragm subassembly 321 continues to sense the outlet pressure of the regulator valve 304. As long as the outlet pressure remains approximately equal to the control pressure, the control assembly 322 will balance the valve disc 328 in an open position away from the outlet end 352 of the valve port 336.
For example, if the outlet flow increases, i.e., the demand increases, the outlet pressure will decrease below the control pressure. The diaphragm senses the decrease in outlet pressure and the spring 330 expands and moves the diaphragm 324 and piston 332 downward to move the valve disc 328 away from the valve port 336 and further open the regulator valve 304. Alternatively, however, if the outlet flow decreases, i.e., the demand decreases, the outlet pressure will increase above the control pressure set by the control spring 330. Therefore, the diaphragm 324 senses the increased outlet pressure and moves upward against the bias of the control spring 330 to move the valve disc 328 back toward the valve port 336. Accordingly, in the event that the downstream demand completely stops, gas will continue to flow through the regulator valve 304 and increase the downstream pressure sufficiently to move the valve disc 328 into engagement with the outlet end 352 of the valve port 336, as depicted.
FIG. 3A depicts the valve port 336 of FIG. 3, which is constructed in accordance with one embodiment of the present invention. The valve port 336 includes a one-piece body similar to the conventional valve port 136 described above with reference to FIG. 1A. The valve port 336 includes a valve seat 338, a hexagonal nut portion 340, and a body portion 342. The valve seat 338 protrudes from the nut portion 340 and is adapted to be engaged by the seating surface 388 of the valve disc 328 to close the regulator valve 304 and prevent the flow of gas through the regulator 300, as depicted in FIG. 3. The body portion 342 includes a plurality of external threads 343 in threaded engagement with the throat 310 of the regulator valve 304. The hexagonal nut portion 340 is adapted to be engaged by a tool such as a pneumatic ratchet, for example, to install the valve port 336 into the regulator valve 304. Additionally, as depicted, the valve port 336 defines the elongated orifice 344 for allowing the passage of gas through the regulator valve 304, as mentioned above. Accordingly, the valve port 336 is removable from the regulator valve 304 such that it may be replaced with a different valve port having a different configuration to tailor operational and flow characteristics of the regulator valve 304 to a specific application.
The orifice 344 of the valve port 336 of the embodiment depicted in FIG. 3A defines an inlet aperture 347, a transition aperture 349, an outlet aperture 351, an inlet portion 344 a, and an outlet portion 344 b. The inlet aperture 347 is disposed proximate to the inlet end 350 of the valve port 336 and the outlet aperture 351 is disposed proximate to the outlet end 352 of the valve port 336. The inlet portion 344 a extends between the inlet aperture 347 and the transition aperture 349. The outlet portion 344 b extends between the transition aperture 349 and the outlet aperture 351. In the disclosed embodiment, the inlet, transition, and outlet apertures 347, 349, 351 can have circular cross-sections. The transition and outlet apertures 349, 351 have a common diameter D1. Therefore, the outlet portion 344 b of the orifice 344 includes a generally uniform diameter D1 that is equal to the diameter D1 of the transition and outlet apertures 349, 351.
The inlet aperture 347 of the disclosed embodiment, however, has a diameter D2 that is larger than the diameter D1 of the transition and outlet apertures 349, 351. Therefore, the inlet portion 344 a of the disclosed embodiment includes a sidewall 345 that generally uniformly converges from the inlet aperture 347 to the transition aperture 349. Therefore, in one embodiment, the sidewall 335 of the inlet portion 344 a can be a frustoconical, or a tapered, sidewall. In the disclosed embodiment, the sidewall 345 may converge at an angle α that is between approximately 15° and approximately 75°, and at least in one embodiment, approximately 45°.
Additionally, in the disclosed embodiment, the diameter D2 of the inlet aperture 347 may be between approximately 10% and approximately 150% larger than the diameter D1 of the transition and outlet apertures 349, 351. Further still, the inlet portion 344 a of the disclosed embodiment constitutes a majority of the length of the orifice 344. For example, the inlet portion 344 a includes a longitudinal dimension L1 that is larger than a longitudinal dimension L2 of the outlet portion 344 b. In one embodiment, the longitudinal dimension L1 of the inlet portion 344 a may be between approximately 10% and approximately 150% larger than the longitudinal dimension of the outlet portion 344 b, and at least in one embodiment, approximately 100% larger.
In alternative embodiments, however, the diameters of the inlet, transition, and outlet apertures 347, 349, 351 may not be limited to the ranges provided above. In still further alternative embodiments, the inlet and outlet portions 344 a, 344 b may be configured such that the longitudinal dimension L1 of the inlet portion 344 a may be equal to or smaller than the longitudinal dimension L2 of the outlet portion 344 b. Regardless of the specific arrangement, the orifice 344 of the present embodiment maximizes the flow capacity of the valve port 336 by minimizing the detrimental effects of basic fluid dynamics such as boundary layer fluid separation.
For example, the valve port 336 of the present embodiment advantageously directs gas flowing through the regulator valve 304 along a flow path, which may be indicated by flow arrows 346 in FIG. 3A. More particularly, the flow of gas enters the increased diameter D2 of the inlet aperture 347 of the orifice 344. As the gas flows through the inlet portion 344 a, the convergent sidewall 345 directs the gas to conform with the dimensions of the transition aperture 349 and the outlet portion 344 b of the orifice 344. This direction advantageously increases the pressure of the gas within the outlet portion 344 b and thereby reduces the effects of boundary layer fluid separation adjacent to the sidewalls of the outlet portion 344 b and maximizes the capacity of the valve port 336. Accordingly, the valve port 336 of the present embodiment includes an effective diameter D3, which is defined by the diameter of the flow of gas emerging from the outlet portion 344 b of the orifice 344. The effective diameter D3 is substantially equal to the diameter D1 of the outlet portion 344 b and the full potential of the flow capacity of the valve port 336 is approximately realized.
FIG. 4 depicts another embodiment of a valve port 436 constructed in accordance with the principles of the present invention for being installed within the throat 310 of the regulator valve 304 of FIG. 3. The valve port 436 depicted in FIG. 4 is similar to the conventional valve port 236 described above with reference to FIG. 2 in that it is configured to provide a primary seal and a secondary, or back-up, seal. The valve port 436 generally includes a housing 460, a cartridge 462, and a spring 464. The cartridge 462 is slidably disposed within the housing 460 and includes an inlet end 462 a, an outlet end 462 b, and an elongated orifice 444 extending between the inlet end 462 a and the outlet end 462 b. The spring 464 biases the cartridge 462 into a first position depicted in FIG. 4, which corresponds to a position for providing the primary seal.
The housing 460 includes a generally cylindrical housing having a hexagonal nut portion 466, a body portion 468, and a curtain portion 470. The nut portion 466 and the body portion 468 cooperatively, or in combination, define an internal cavity 474 accommodating the cartridge 462. Generally, the cavity 474 includes a first portion 474 a and a second portion 474 b. The diameter of the first portion 474 a is smaller than the diameter of the second portion 474 b in the embodiment of the valve port 436 depicted in FIG. 4. Additionally, the body portion 468 includes a plurality of external threads 472 for being threadably coupled into the throat 310 of the regulator valve 304. The nut portion 466 of the housing 460 is therefore adapted to be engaged by a tool such as a pneumatic ratchet to install the valve port 436 into the regulator valve 304. Accordingly, the valve port 436 is removable from the regulator valve 304 such that it may be replaced with a different valve port having a different configuration to tailor operational flow characteristics of the regulator valve 304 to a specific application.
The first portion 474 a of the cavity 474 slidably accommodates the inlet end 462 a of the cartridge 462, and the second portion 474 b slidably accommodates the oulet end 462 b of the cartridge 462, as depicted. A step 476 disposed between the first and second portions 474 a, 474 b limits displacement of the cartridge 462 away from the curtain portion 470 of the housing 460. The curtain portion 470 includes a plate 480 spaced from the body portion 468 of the housing 460 by a pair of legs 482, only one of which is depicted in FIG. 4 due to the cross-sectional nature of the illustration. The plate 480 of the disclosed embodiment includes a solid circular plate that serves as a spring seat 471. So configured, the curtain portion 470 defines a pair of windows 484 in the housing 460 for allowing gas to flow into the valve port 436.
As mentioned, the cartridge 462 includes an inlet end 462 a, an outlet end 462 b, and an elongated orifice 444 extending between the inlet end 462 a and the outlet end 462 b. The orifice 444 defines a receiving aperture 445, an inlet aperture 447, a transition aperture 449, and an outlet aperture 451. The receiving and inlet apertures 445, 447 are disposed proximate to the inlet end 462 a of the cartridge 462, and the transition and outlet apertures 449, 451 are disposed proximate to the outlet end 462 b of the cartridge 462. So configured, the orifice 444 includes a receiving portion 444 a, an inlet portion 444 b, and an outlet portion 444 c. The receiving aperture 445 is disposed adjacent to the inlet end 462 a of the valve port. The outlet aperture 451 is disposed adjacent to the outlet end 462 b of the valve port 436. In the disclosed embodiment, each of the apertures 445, 447, 449, 451 have circular cross-sections. The outlet and transition apertures 451, 449 share a common diameter D1. The inlet aperture 447 has a diameter D2. The receiving aperture 445 has a diameter D3. In the disclosed embodiment, the diameter D2 of the inlet aperture 447 is larger than the diameter D1 of both the outlet and transition apertures 451, 449. Additionally, the diameter D3 of the receiving aperture 445 is larger than the diameter D2 of the inlet aperture 447.
The receiving portion 444 a is generally uniformly cylindrical and extends between the receiving aperture 445 and the inlet aperture 447. Additionally, the receiving portion 444 c of the disclosed embodiment defines a chamfered inner surface 492 disposed adjacent to the receiving aperture 445. Similarly, the outlet portion 444 c extends between the transition aperture 449 and the outlet aperture 451, and therefore, is also generally cylindrical. The inlet portion 444 b extends between the inlet aperture 447 and the transition aperture 449. As mentioned above, the diameter D2 of the inlet aperture 447 is larger than the diameter D1 of the transition aperture 449, and therefore, the inlet portion 444 b of the orifice 444 includes a sidewall 435 that converges from the inlet aperture 447 toward the transition aperture 449. In the disclosed embodiment, the inlet portion 444 b generally uniformly converges at an angle β of between approximately 15° and approximately 85°, and at least in one embodiment, approximately 75°. In one embodiment, the sidewall 435 of the inlet portion 444 b can be frustoconical, or generally tapered, for example. Furthermore, in the disclosed embodiment, the diameter D2 of the inlet aperture 447 may be between approximately 10% and approximately 150% larger than the diameter D1 of the transition aperture 449. However, alternative embodiments may not be limited to such a range of relative dimensions and/or angles.
Further still, as depicted in FIG. 4, the inlet portion 444 b of the orifice 444 includes a longitudinal dimension L1 that is larger than a longitudinal dimension L2 of the outlet portion 444 c. In one embodiment, the longitudinal dimension L1 of the inlet portion 444 b may be between approximately 10% and approximately 150% larger than the longitudinal dimension L2 of the outlet portion 444 c, and at least in one embodiment, approximately 100% larger. However, alternative embodiments may be configured such that the longitudinal dimension L1 of the inlet portion 444 b may be equal to or smaller than a longitudinal dimension L2 of the outlet portion 444 c. Regardless of the specific arrangement, the orifice 444 of the embodiment of the valve port 436 disclosed in FIG. 4 maximizes flow capacity through the cartridge 462 by minimizing the effects of boundary layer fluid dynamics.
For example, similar to that which was described above with reference to the valve port 336 depicted in FIG. 3, the valve port 436 of the present embodiment advantageously directs gas flowing through the regulator valve 304 along a flow path, which may be indicated by flow arrows 446 in FIG. 4. More particularly, the flow of gas enters the receiving portion 444 a of the orifice 444 of the cartridge 462, the diameter D3 of which is larger than the diameter of the remainder of the orifice 444, in the disclosed embodiment. As the gas flows through the receiving portion 444 a, it is directed into the inlet portion 444 b, via the inlet aperture 447. The convergent sidewall 435 of the inlet portion 444 b directs the gas to closely conform to the dimensions of the transition aperture 449 and the outlet portion 444 c of the orifice 444. This direction advantageously increases the pressure of the gas flowing through the outlet portion 444 c and thereby reduces the effects of boundary layer fluid separation adjacent to the sidewalls of the outlet portion 444 c and maximizes the capacity of the valve port 436.
Accordingly, the valve port 436 of the present embodiment includes an effective diameter D4, which is defined by the diameter of the flow of gas emerging from the outlet portion 444 b of the orifice 444. The effective diameter D4 is substantially equal to the diameter D1 of the transition and outlet apertures 449, 451 and the outlet portion 444 c of the orifice 444.
Similar to the conventional valve port 236 described above with reference to FIG. 2, during a normal operational condition, the outlet end 462 b of the cartridge 462 serves as a primary seat and is adapted to be engaged by the valve disc 328 of the control assembly 322 depicted in FIG. 3, for example, to stop the flow of fluid through the regulator valve 304. However, in the event that debris or some other type of foreign material becomes lodged between the valve disc 328 and the outlet end 462 b of the cartridge 462, the primary seal fails to stop the flow of gas through the valve port 436. Thus, gas continues to flow through the regulator valve 304 and the pressure downstream of the regulator 10, i.e., the outlet pressure, increases. This increase in pressure is sensed by the diaphragm 324 which further causes the valve disc 328 to be forced toward the valve port 436. This force eventually overcomes the force of the spring 464 and displaces the cartridge 462 into the housing 460 such that the inlet end 462 a engages the secondary seat 471. So configured, the secondary seat 471 of the housing 460 seals the inlet end 462 a and blocks the flow of gas through the windows 484 in the housing 460, thereby preventing the flow of gas through the orifice 444 in the cartridge 462 and the regulator valve 304.
Once a downstream demand is placed back on the system however, the diaphragm 324 senses a decrease in outlet pressure and moves the valve disc 328 away from the valve port 436. The spring 464 biases the cartridge 462 back to the position depicted in FIG. 4 and any debris previously lodged between the valve disc 328 and the outlet end 462 a of the cartridge 462 releases and flows downstream.
In light of the foregoing, it should be appreciated that the present invention provides a valve port 336, 436 defining an orifice 344, 444 for maximizing the flow capacity of the valve port 336, 436. For example, the valve ports 336, 436 include orifices 344, 444 that function as nozzles to compress the flow of gas at respective outlet portions thereof to reduce the effects of boundary layer separation and maximize the flow capacity of the valve ports. While various embodiments of the of valve ports having orifices of various geometrical cross-sections have thus far been described, alternative embodiments having different geometries are intended to be within the scope of the present invention. For example, FIG. 5 depicts an alternative cartridge 562 adapted for use with the valve port 436 described above with reference to FIG. 4.
Similar to the cartridge 462 described above, the cartridge 562 depicted in FIG. 5 includes an inlet end 562 a, an outlet end 562 b, and an elongated orifice 544 extending between the inlet end 562 a and the outlet end 562 b. The orifice 544 defines a receiving aperture 545, a first transition aperture 547 a, an inlet aperture 549, a second transition aperture 547 b, and an outlet aperture 551. The receiving, first transition, and inlet apertures 545, 547 a, 549 are disposed proximate to the inlet end 526 a of the cartridge 562, when compared to the second transition and outlet apertures 547 b, 551, which are disposed proximate to the outlet end 562 b of the cartridge 562. Additionally, the orifice 544 includes a receiving portion 544 a, a transition portion 544 b, an inlet portion 544 c, and an outlet portion 544 d. The receiving portion 544 a of the embodiment of the cartridge 562 depicted in FIG. 5 also includes an inner chamfered surface 592 disposed adjacent to the receiving aperture 545.
Each of the apertures 545, 547 a, 547 b, 549, 551 have circular cross-sections. The outlet aperture 551 and the second transition aperture 547 b share a common diameter D1. The inlet aperture 549 and the first transition aperture 547 a have a common diameter D2. The receiving aperture 545 has a diameter D3. In the disclosed embodiment, the diameter D2 of the inlet aperture 549 is larger than the diameter D1 of the outlet aperture 551 and the second transition aperture 547 b. Additionally, the diameter D3 of the receiving aperture 545 is larger than the diameter D2 of the inlet aperture 549.
The receiving portion 544 a of the orifice 544 is generally uniformly cylindrical and extends between the receiving aperture 545 and the first transition aperture 547 a. Similarly, the transition portion 544 b of the orifice 544 is generally uniformly cylindrical and extends between the first transition aperture 547 a and the inlet aperture 549. Moreover, the outlet portion 544 d of the orifice extends between the second transition aperture 547 b and the outlet aperture 551, and therefore, is also generally cylindrical.
In contrast, the inlet portion 544 c extends between the inlet aperture 549 and the second transition aperture 547 b. As stated above, the diameter D1 of the second transition aperture 547 b is smaller than the diameter D2 of the inlet aperture 549. Accordingly, the inlet portion 544 c includes a sidewall 535 that generally uniformly converges from the inlet aperture 549 toward the second transition aperture 547 b. Therefore, in the disclosed embodiment, the sidewall 535 of the inlet portion 544 c can be considered a frustoconical, or tapered, sidewall that converged at an angle φ of between approximately 15° and approximately 85°, and at least in one embodiment, approximately 45°. Furthermore, in one embodiment, the diameter D2 of the inlet aperture 549 may be between approximately 10% and approximately 150% larger than the diameter D1 of the second transition aperture 547 b and the outlet portion 544 d of the orifice 544, and at least in one embodiment, approximately 50% larger. However, alternative embodiments may not be limited to such a range of relative dimensions and/or angles.
Further still, as depicted in FIG. 5, a longitudinal dimension L1 of the transition portion 544 b and the inlet portion 544 c combined is larger than a longitudinal dimension L2 of the outlet portion 544 d. In one embodiment, the longitudinal dimension L1 may be between approximately 10% and approximately 300% larger than the longitudinal dimension L2, and at least in one embodiment, approximately 200% larger. However, alternative embodiments may be configured such that the longitudinal dimension L1 may be equal to or smaller than the longitudinal dimension L2. Regardless of the specific arrangement, the orifice 544 of the embodiment of the cartridge 563 disclosed in FIG. 5 provides the same advantages as the cartridge 462 depicted in FIG. 4.
Specifically, the cartridge 562 of the present embodiment includes an effective diameter D4, which is defined by the diameter of the flow of gas emerging from the outlet portion 544 d of the orifice 544. The effective diameter D4 is substantially equal to the diameter D1 of the outlet aperture 551 and the outlet portion 544 d of the orifice 544. Accordingly, the orifice 544 of the present embodiment advantageously maximizes the flow capacity of the cartridge 562 by offsetting the effects of boundary layer fluid separation otherwise present in conventional valve ports.
As stated above, the present invention is not intended to be limited to the examples provided herein. Alternative embodiments may include additional features to help increase flow capacity or other performance characteristics of a valve port constructed in accordance with the principles of the present invention. For example, one alternative embodiment of the valve port 336 described above with reference to FIG. 3A may include a bull-nosed, or rounded, transition between the inlet portion 344 a and the outlet portion 344 b of the orifice 344. Such a bull-nosed transition may further assist the valve body in decreasing the effects of boundary layer separation. The same concept could also be applied to any of the transitions between the different portions of the orifices 444, 544 of the cartridges 462, 562 described with reference to FIGS. 4 and 5.
Furthermore, while the cartridges 462, 562 have been disclosed as including chamfered inner surface 492, 592 disposed adjacent to the respective receiving apertures 435, 535, alternative embodiments may not include chamfered surface or alternatively, may include bull-nosed surfaces, for example, for helping reduce the effects of boundary layer fluid separation. Nevertheless, in the embodiment disclosed as having chamfered inner surfaces 492, 592, such chamfered inner surfaces 492, 592 may be disposed at an angle γ, as depicted in FIG. 5, for example, that is between approximately 5° and approximately 75°, and at least in one embodiment approximately 30°. Still further embodiments may include chamfered inner surfaces that do not fall within this prescribed range of angles.
Further yet, while the valve ports 336, 436 of the embodiments disclosed herein have been described as having orifices 344, 444, 544 that are generally circular in cross-section, alternative embodiments may not be so limited. For example, in alternative embodiments, the orifices may have square, rectangular, or some other geometrical cross-section capable of serving the principles of the present invention.
Finally, while the various converging inlet portions 344 a, 444 b, 544 c of the valve ports 336, 436 have been disclosed herein as including generally frustoconical sidewalls 335, 435, 535, in alternative embodiments, the converging inlet portions 344 a, 444 b, 544 c can include convex radiused profiles, for example. Such convex radiused profiles could resemble bullnosed surfaces in one embodiment. Thus, the terms converge, converging, and/or convergent, as used in the present description, are intended to describe one or more geometries that taper, move, draw, or come together. It should be appreciated that these terms are not limited to the linearly converging frustoconical geometries expressly depicted herein, but rather, are intended to include any geometry separated by orifices of different dimensions. In one embodiment, the converging geometry could even include a plurality of steps.
Thus, the regulators and valve ports described herein are merely examples of fluid control devices incorporating the principles of the present invention. Other fluid control devices such as control valves may also benefit from the structures and/or advantages of the present invention.

Claims

1. A fluid regulating device comprising:

a valve body having a valve body inlet, a valve body outlet, and a throat disposed between the valve body inlet and the valve body outlet;

a control element disposed within the valve body and adapted to be displaced between an open position and a closed position for controlling the flow of fluid through the valve body;

an actuator coupled to the valve body and including a diaphragm operably coupled to the control element, the diaphragm responsive to a pressure at the valve body outlet for moving the control element between the open and closed positions; and

a valve port carried by the throat of the valve body and comprising a primary valve seat adapted to be engaged by the control element when the control element is in the closed position to prevent the flow of fluid through the valve body, the valve port further comprising:

a valve port inlet, a valve port outlet, and an elongated orifice extending between the valve port inlet and the valve port outlet,

the elongated orifice comprising a frustoconical portion extending from a location proximate to the valve port inlet to a location proximate to the valve port outlet, thereby enabling fluid to flow through the valve port in a manner that reduces boundary layer separation and maximizes flow capacity.

2. The device of claim 1, wherein the frustoconical portion converges at an angle in the range of approximately 15° to approximately 85°.

3. The device of claim 1, wherein the valve port further comprises a first aperture defining a first end of the frustoconical portion that is proximate to the valve port inlet, and a second aperture defining a second end of the frustoconical portion that is proximate to the valve port outlet, the first aperture having a diameter that is larger than a diameter of the second aperture.

4. The device of claim 3, wherein the first diameter is in the range of approximately 10% to approximately 150% larger then the second diameter.

5. The device of claim 1, wherein the frustoconical portion comprises a majority of the elongated orifice.

6. The device of claim 1, wherein the valve port is threadably connected to the throat of the valve body.

7. The device of claim 1, wherein the valve port comprises a housing and a cartridge slidaby disposed in the housing, the cartridge defining the primary valve seat, the elongated orifice, the valve port inlet, and the valve port outlet.

8. The device of claim 7, wherein the housing comprises a secondary valve seat disposed opposite the cartridge from the primary valve seat and the cartridge is slidably disposed in the housing between a primary seating position where the valve port inlet is spaced from the secondary valve seat, and a secondary seating position where the valve port inlet sealingly engages the secondary valve seat.

9. The device of claim 8, wherein the housing further comprises at least one window disposed adjacent the secondary seat for allowing the passage of fluid into the elongated orifice when the cartridge is in the primary seating position.

10. A fluid regulating device comprising:

a valve port inlet, a valve port outlet, a first aperture disposed proximate to the valve port inlet, a second aperture disposed proximate to the valve port outlet, and an elongated orifice extending between the first and second apertures,

the first orifice having a first diameter, the second orifice having a second diameter that is smaller than the first diameter such that the elongated orifice converges from the first aperture to the second aperture to enable fluid to flow through the valve port in a manner that reduces boundary layer separation and maximizes flow capacity.

11. The device of claim 10, wherein the first diameter is in the range of approximately 10% to approximately 150% larger then the second diameter.

12. The device of claim 10, wherein the elongated orifice comprises a frustoconical portion extending from the first aperture to the second aperture.

13. The device of claim 12, wherein the frustoconical portion converges from the first aperture to the second aperture at an angle in the range of approximately 15° to approximately 85°.

14. The device of claim 12, wherein the frustoconical portion comprises a majority of the elongated orifice.

15. The device of claim 10, wherein the valve port is threadably connected to the throat of the valve body.

16. The device of claim 10 wherein the valve port comprises a housing and a cartridge slidaby disposed in the housing, the cartridge defining the primary valve seat, the elongated orifice, the valve port inlet, the valve port outlet, the first aperture, and the second aperture.

17. The device of claim 16, wherein the housing comprises a secondary valve seat disposed opposite the cartridge from the primary valve seat and the cartridge is slidably disposed in the housing between a primary seating position where the valve port inlet is spaced from the secondary valve seat, and a secondary seating position where the valve port inlet sealingly engages the secondary valve seat.

18. The device of claim 17, wherein the housing further comprises at least one window disposed adjacent the secondary seat for allowing the passage of fluid into the elongated orifice when the cartridge is in the primary seating position.

19. A valve port adapted for use with a fluid regulating device including a valve body, a control element, and an actuator, the control element being disposed within the valve body and adapted to be displaced between an open position and a closed position for controlling the flow of fluid through the valve body, the actuator being coupled to the valve body and including a diaphragm that is operably coupled to the control element and responsive to a pressure at an outlet of the valve body for moving the control element between the open and closed positions, the valve port adapted to be removably disposed in the throat of the fluid regulating device and comprising:

a primary valve seat adapted to be engaged by the control element when the control element is in the closed position to prevent the flow of fluid through the valve body;

a valve port inlet and a valve port outlet disposed opposite the valve port inlet; and

an elongated orifice extending between the valve port inlet and the valve port outlet, the elongated orifice comprising a frustoconical portion extending from a location proximate to the valve port inlet to a location proximate to the valve port outlet, thereby enabling fluid to flow through the valve port in a manner that reduces boundary layer separation and maximizes flow capacity.

20. The valve port of claim 19, wherein the frustoconical portion converges at an angle in the range of approximately 15° to approximately 85°.

21. The valve port of claim 19, further comprising a first aperture defining a first end of the frustoconical portion that is proximate to the valve port inlet, and a second aperture defining a second end of the frustoconical portion that is proximate to the valve port outlet, the first aperture having a diameter that is larger than a diameter of the second aperture.

22. The valve port of claim 21, wherein the first diameter is in the range of approximately 10% to approximately 150% larger then the second diameter.

23. The valve port of claim 19, wherein the frustoconical portion comprises a majority of the elongated orifice.

24. The valve port of claim 19, wherein the valve port comprises a housing and a cartridge slidaby disposed in the housing, the cartridge defining the primary valve seat, the elongated orifice, the valve port inlet, and the valve port outlet.

25. The valve port of claim 24, wherein the housing comprises a secondary valve seat disposed opposite the cartridge from the primary valve seat and the cartridge is slidably disposed in the housing between a primary seating position where the valve port inlet is spaced from the secondary valve seat, and a secondary seating position where the valve port inlet sealingly engages the secondary valve seat.

26. The valve port of claim 25, wherein the housing further comprises at least one window disposed adjacent the secondary seat for allowing the passage of fluid into the elongated orifice when the cartridge is in the primary seating position.